Husbands who are not where they are supposed to be could soon be in danger of being “sniffed” out by a mobile phone service that gives suspicious partners an electronic map showing the location of their spouse.

The Social Network Integrated Friend Finder (Sniff) is a new application, accessed via Facebook or mobile phone, which could bring an end to frantic “Where r u?” text messages.

The service, popular in Scandinavia, promises to provide users with a detailed map of their friends’ locations, any time and anywhere. However, there are fears that Sniff could be abused by employers to remove the last vestiges of privacy from staff.

Useful Networks, the American company behind Sniff, promised that only consumers who gave their permission could be electronically tracked by the service, which operates across all mobile carriers. Users can specify who can and can not sniff them, or whether they are open to be sniffed by anyone on the network. The company plans to charge users about 75p for each location “sniff”, with the results for mobile customers sent by return text. It will be the first Facebook application to apply premium charges to customers’ mobile bills. The heaviest users in Sweden are wireless-connected members of the social networking site, who have integrated the application into their personal profile page.

“Sniffing” works through similar technology used by the police to track down suspected terrorists or missing children via their mobile phones. The phone sends a signal to nearby base stations. Positioning software performs a triangulation calculation on the information from the base stations and converts it into a geographical location.

Brian Levin, chief executive officer of Useful Networks, told The Times: “Privacy is paramount and sniffing should only be used by people you can trust. It is a fun way to solve the proven most popular text message, ‘Where r u?’”

Travellers who find themselves lost in a new city could also make use of the service. “You can ‘sniff’ yourself if you really need to,” Mr Levin said.

But employees who are enjoying a long lunch or a secret liaison instead of the business meeting in their diary could also find themselves “sniffed out”. Mr Levin said: “If the employer is paying the phone bill and employees are aware they can be ‘sniffed’, at least everyone knows those are the rules.”

Work surveillance is an increasing concern. Last week the German supermarket chain Lidl was accused of using Stasi-style methods to spy on staff and collect personal details.

Mr Levin, who created the text-message voting system for American Idol, also cautioned that sniffing should not be relied upon by parents to track their young children: the service will only place a location within a radius of about 200m (650ft).

Useful Networks, owned by the American giant Liberty Media, hopes to introduce “sniffing” in Britain this month.

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